1. Field of the Invention
The present invention relates to modification of a steering shaft supporting structure of a vehicle.
2. Description of Background Art
A structure for supporting an input shaft and an output shaft of a power steering system respectively with different constituent members of a vehicle body frame has been heretofore known as a conventional type of a steering shaft supporting structure of a vehicle. See, Japanese Patent Laid-open Official Gazette No. 2004-23101.
The following configuration is described in FIG. 4 of Japanese Patent Laid-open Official Gazette No. 2004-23101. In this configuration, an upper shaft 50a of a steering shaft 50 is rotatably attached to an upper pipe 18 constituting a vehicle body frame by use of a shaft supporting member 52, an end of a lower shaft 50b provided to an electrically-operated power steering system is linked to the upper shaft 50a by use of a universal joint 51, and the other end of the lower shaft 50b is rotatably attached to a lower bracket 54 provided to a front cross pipe 23 by use of a gear case 55.
The upper shaft 50a and the lower shaft 50b constituting the steering shaft 50 are supported respectively by different members which are the upper pipe 18 and the front cross pipe 23. As a result, the distance between, and a positional relation between, the shaft supporting member 52 near the upper shaft 50a and the lower bracket 54 near the lower shaft 50b vary, for example, due to inaccuracy in manufacturing the vehicle body frame, and due to change in shape of the vehicle body frame which is caused when an external force works on the vehicle body frame. If this variation becomes larger, the universal joint 51 is not capable of accommodating this variation. Accordingly, the supporting of the electrically-operated power steering system becomes susceptible to the variation.